[Leukemia in sheep on a state farm]. / Prouchvane na levkoza po ovtsete v edna obshtestvena ferma.

Leukosis was diagnosed in a flock of sheep. It was studied epizootiologically, clinically, morphologically, virologically, and serologically in the course of two years. Fifteen sheep manifested clinical symptoms of the disease. Involved were the lymph nodes (superficial, skeletal, and visceral), liver, spleen, heart, and kidneys. Histologically, there were diffuse or limited lymphoid cell proliferations, some of them showing small unreactive cell elements. Sixty-two out of 160 serologically studied sheep showed in their sera antibodies against the virus of bovine leukosis as established by means of the agglutination immunodiffusion test. The leukosis virus was obtained from lymphocyte cultures isolated from infected sheep. It was used in the production of an antigen. A specific precipitation line was produced in the interaction between the sheep leukotic antigen and the bovine leukotic serum in the agglutination immunodiffusion test. Such data spoke of the antigenic similarity between the virus isolated from leukotic sheep and the virus isolated from leukotic cattle. The slaughterhouse inspection of 157 clinically normal sheep revealed tumoral lesions in 4 more animals. The changes were seen in the lymph nodes. No such changes were observed in the parenchymal organs.

[Viral carrier state and viral excretion in classical swine fever]. / Prouchvane vurkhu virusonositelstvoto i virusootdelitelstvoto pri klasicheskata chuma po svinete.

Studies on swine pest virus carrying and elimination on swine vaccinated by lapinizated vaccine strain "K" from rabbits were performed. Vaccinated swine were injected with the pathogenic virus on the 60th day post vaccination and to them were added not immunized swine with the aim to discover virus elimination. The experimental swine were decapitated on the 3, 5, 6 and 7th day post infection. Alternating passages were made by emulsion of the inner organs of these swine on not immunized swine as well as pathohistological investigation of the parenchymal organs and the brain. Presence of the virus and of pathohistological changes were not detected 7 days post injection of the virulent virus. Contact having swine which served as a indicator for virus elimination were observed for 21 days, but remained healthy. These swine, when infected with the virulent virus, suffered from pest.

[Production and titration of a vaccine against the infectious encephalomyelitis of poultry]. / Poluchavane i titrirane na vaksina sreshtu zarazen entsefalomielit po ptitsite.

A vaccine was produced against infectious encephalomyelitis of day-old chicks infected cerebrally with strain Calnek 1143. It is a brain suspension from killed birds that have shown disease symptoms, treated with penicillin and streptomycin and stored at -20 degrees C. Experiments were carried out to titrate the vaccine through determining the minimum infective dose for day-old chicks treated with 0.1 cm3 each of it, orally, as obtained from tenfold dilutions. It was found that birds do not manifest clinically the disease, however, with birds killed 20--25 days following infection there have been characteristic histologic changes speaking of infectious encephalomyelitis. The minimum infective dose of the various batches of vaccine have been found to range from 10(-3) to 10(-5)/cm3. Applied under the conditions of the practice the vaccine has proved harmless, contributing to eradication of the disease on the infected farms.

[Diagnosis of infectious anemia in horses using the Coggins test]. / Diagnostika na infektsioznata anemiia po konete s testa na Coggins.

Coggins' immune diffusion test was modified, and was applied as a screening one in the study of the epizootic status. The positive reactions were characterized by the production of a precipitation line between the antigen and the respective serum that was tested. The appearance of such a line was associated with that formed with the use of the positive control serum, pointing to a reaction of identity. With the weakly positive reactions the ends of the precipitin lines, formed with the use of the positive control serum, were found to deviate slightly toward the site where the antigen had been placed. The specificity of the test was confirmed through biological experiments and clinical, morphological, and hematological investigations.

[Candida infections in farm animals and birds]. / Prouchvane na kandidozata po selskostopanskite zhivotni i ptitsi.

Studied were swab samples taken from the oral cavity, the nostrils, and the rectum, resp., the cloaca of a total of 2315 calves, pigs, chickens, poulets, and turkey-poults to demonstrate the presence of fungi of the genus Candida. The material was taken from healthy animals and birds as well as from such that had digestive troubles, bronchitis, and bronchopneumontia. Isolated were the species; C. krusei, C. tropicalis, C. parapsilosis, C. albicans, C. pelliculosa, C. gulliermondii, and C. utilis. The various species were differentiated on the basis of their morphologic and cultural characteristics and their biochemical behaviour. It was established that C. albicans only manifested pathogenic properties. It was experimentally demonstrated that the appearance of a Candida infection was facilitated by the simultaneous application of a fungus culture and antibiotics of a broad spectrum. Histopathologic investigations were carried out of experimentally infected and spontaneously affected birds.

[Pathomorphological studies of trichocephaliasis in sheep]. / Patomorfologichni izsledvaniia na trikhotsefalozata po ovtsete.

The morphologic study of 22 sucking and weaned lambs (8 experimentally and 14 spontaneously infected with Trichocephalus) revealed that in its biologic development in the host Trichocephalus fixes itself firmly and penetrates deeply at its head and into the mucous membrane of the caecum and the large intestine. Besides, at these sites morphologic lesions in cases of strong infection have been established in the liver, kidneys, spleen, and lung. The desquamated epithelial cells and the erythrocytes found in the digestive canal of the parasite showed that sheep Trichocephalus sp. are hematophages. The indented chitin cover and its morphologic peculiarities is a structural anatomic and biologic adaptation enabling the fixing and dependable adherence to the intestinal mucous membrane of the host.

[Comparative study of infectious and atypical encephalomyelitis in birds]. / Sravnitelni prouchvaniia na infektsiozniia i atipichniia entsefalomielit po ptitsite

Studied were morphologically a total of 234 birds for infectious encephalomyelitis (IE) and atypic encephalomyelitis (AE) of which 70 were experimentally infected with standard reference strains of IE (Calnek 1143-42 birds, and Van Roeckel 28 birds), 32 were infected with a brain suspension of affected with AE birds, and 110 were spontaneously affected with AE. Those of the birds that were infected with the standard strains of IE as well as with the brain suspension exhibited changes in the central nervous system in the form of a non-suppurative encephalomyelitis, and in the viscera--lymphoidcell proliferations. These alterations proved analogous with those observed in birds spontaneously affected with AE. The changes in CNS in the case of IE were localized in the brain and the spinal cord, while the lesions in the case of AE were found chiefly in the brain. In AE there were perivascular lymphoidcell were groupings along the peripheral nerves. It was concluded that the histologic changes established may well serve to differentiate IE from AE in Marek's disease, the transitional paralysis, the Newcastle disease, and the alimentary encephalomalacia.

[Study of the pathogenic qualities of 4 celo-virus strains isolated in Bulgaria]. / Prouchvane patogennite kachestva na chetiri selo-virusni shtama, izolirani u nas

Four CELO virus strains, isolated in this country, were used to infect 3-day-old chicks via the trachea, muscularly, orally, subcutaneously, and cerebrally. The chicks were killed on the 2nd, 4th, 6th, 9th and 16th day following inoculation. Material was taken from each chick for morphologic, virologic, and serologic examination. The clinical course of the disease was also followed up. Prior to killing some birds showed infirmity, difficult breathing, slightly expressed diarrhia, going off food, and more sporadically there was fecal mass around the cloaca matting the plumage. Some manifested nervous symptoms similar to those observed in cases of Newcastle disease and encephalitis of birds. In some of the chicks there were hyperemia of the lungs, trachea, and intestins as well as necrotic foci in the liver.

[Hepatoma in artificially raised trout]. / Khepatoma u izkustveno razv'zhdani p'st'rvi

Cases were described of a hepatoma in the liver of trout, Salmo irideus, Gibb., originating from three fish-breeding farms in the district of Sofia. Histologically, three were tumor cells arranged in the form of trabeculae and paths or distributed focally. The tumorous growths had trabeculous, more rarely alveolar structure. Some of the neoplasms had carcinomatous character. The tumor stroma had weakly developed, however, in some parts three was rich fibrous stroma, and the gross appearance resembled fibroadenoma. Infiltrative growth was also observed. It is concluded that the hepatoma observed in poikilothermic animals (rainbow trout) is similar to the liver tumors found in birds and mammals.